Despite carrying user-generated content, Wikipedia has often been criticised for being tough to edit - even by its co-founder Jimmy Wales. But researchers have found another way in which the Web 2.0 wonder might leave people gnashing their teeth: it's much harder to read than that old favourite of doorstep salesmen, Encyclopedia Britannica.

Using what they call "standard readability measures" and statistical analyses of, for example, sentence length and how often easily understood popular words were used, they found Wikipedia lagged in terms of the "readability and comprehensibility" of its content.

The reason is clear, they say: articles on difficult topics are written by experts who sacrifice readability for accuracy - and that is compounded as other experts weigh in with further accuracy-obsessed edits that remove "simplifications, generalisations or intuitive explanations" that might have served to aid readability.

"Modifying [Wikipedia's] editorial guidelines or automatically flagging poorly comprehensible content for revision may be thus needed to improve this situation," the pair conclude. However they only used a small sample of articles. "We now plan to make more extensive comparison to make sure," Jatowt told New Scientist.